Multiresidue Method for Determining Substituted Urea Herbicides in Foods by Liquid Chromatography

1987 ◽  
Vol 70 (4) ◽  
pp. 740-745
Author(s):  
Ronald G. Luchtefeld
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Column Chromatography ◽  
Food Products ◽  
Chemical Derivatization ◽  
Florisil Column ◽  
Average Recovery ◽  
Multiresidue Method ◽  
Florisil Column Chromatography ◽  
Substituted Urea

Abstract A method is described for determining substituted urea herbicides in foods. The residues are extracted from the product with methanol, and the food coextractives are removed by using solvent partitioning and Florisil column chromatography. The extract is analyzed using liquid chromatography with postcolumn photodegradation, chemical derivatization with orthophthalaldehyde, and spectrofluorometry. Recoveries were determined by spiking 8 different food products with 6 phenylureas—chlorbromuron, chloroxuron, diuron, fluometuron, linuron, and metobromuron—at 0.05 and 0.5 ppm. Three determinations were made at each level for each product. Average recovery at 0.05 ppm was 95% (with a standard deviation of 7.9%), and at 0.5 ppm, 98% (with a standard deviation of 6.9%).

Multiresidue Method for Determining Substituted Urea Herbicides in Foods by Liquid Chromatography

1987 ◽  
Vol 70 (4) ◽  
pp. 740-745
Author(s):  
Ronald G Luchtefeld
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Column Chromatography ◽  
Food Products ◽  
Chemical Derivatization ◽  
Florisil Column ◽  
Average Recovery ◽  
Multiresidue Method ◽  
Florisil Column Chromatography ◽  
Substituted Urea

Abstract A method is described for determining substituted urea herbicides in foods. The residues are extracted from the product with methanol, and the food coextractives are removed by using solvent partitioning and Florisil column chromatography. The extract is analyzed using liquid chromatography with postcolumn photodegradation, chemical derivatization with orthophthalaldehyde, and spectrofluorometry. Recoveries were determined by spiking 8 different food products with 6 phenylureas—chlorbromuron, chloroxuron, diuron, fluometuron, linuron, and metobromuron—at 0.05 and 0.5 ppm. Three determinations were made at each level for each product. Average recovery at 0.05 ppm was 95% (with a standard deviation of 7.9%), and at 0.5 ppm, 98% (with a standard deviation of 6.9%).

Volumetric Determination of Malathion, Using Dichlorofluorescein as Indicator

1976 ◽  
Vol 59 (1) ◽  
pp. 216-218
Author(s):  
Miguel Siquiroff ◽  
Ricardo Pollero ◽  
Rodolfo Goyena
Keyword(s):  
Standard Deviation ◽  
Petroleum Ether ◽  
Silver Nitrate ◽  
Ethyl Ether ◽  
Colorimetric Method ◽  
Florisil Column ◽  
Average Recovery ◽  
Florisil Column Chromatography ◽  
Volumetric Determination

Abstract A method has been developed which is based on alkali cleavage of malathion and volumetric determination of the resulting dimethylphosphorodithioate with silver nitrate, using dichlorofluorescein as the indicator. Pure malathion standards were analyzed by the proposed method, yielding a standard deviation of 0.27. Four typical malathion formulations containing talc, wheat flour, and anionic and nonionic emulsifiers were analyzed by both the proposed method and the former official first action colorimetric method with comparable results. Potential interferences from surfactants currently employed in liquid formulations are avoided by the use of Florisil column chromatography. Malathion is eluted from the column with petroleum ether-ethyl ether with an average recovery of 92.5%.

Collaborative Study of Three Methods for the Determination of Fluoride in Vegetation

1978 ◽  
Vol 61 (1) ◽  
pp. 150-153
Author(s):  
Jay S Jacobson ◽  
Laurence I Heller
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Polychlorinated Biphenyls ◽  
Collaborative Study ◽  
Bald Eagle ◽  
Gas Liquid Chromatography ◽  
Tissue Samples ◽  
Florisil Column ◽  
Average Recovery

Abstract A procedure is described for determining Kepone (decachlorooctahydro-l,3,4-metheno-2ffcyclobuta[ cd]pentalene-2-one) residues in avian egg, liver, and tissue. Samples were extracted with benzene-isopropanol, and the extract was cleaned up with fuming H2S04-concentrated H2SO4. Kepone was separated from organochlorine pesticides and polychlorinated biphenyls on a Florisil column and analyzed by electron capture gas-liquid chromatography (GLC). The average recovery from spiked tissues was 86%. The analyses performed on 14 bald eagle carcasses and livers, 3 bald eagle eggs, and 14 osprey eggs show measurable levels which indicate that Kepone accumulates in the tissues of fish-eating birds. Residues were confirmed by GLC-mass spectrometry

Determination of Chlorinated Pesticide Residues in Foods. III. Simultaneous Analysis of Chlorinated Pesticide and Phthalate Ester Residues by Using AgNO3-Coated Florisil Column Chromatography for Cleanup of Various Samples

1979 ◽  
Vol 62 (3) ◽  
pp. 689-694
Author(s):  
Takashi Suzuki ◽  
Kiyoshi Ishikawa ◽  
Nobutoshi Sato ◽  
Kei-Ichi Sakai
Keyword(s):  
Column Chromatography ◽  
Phthalate Esters ◽  
Ethanol Solution ◽  
Simultaneous Analysis ◽  
Phthalate Ester ◽  
Florisil Column ◽  
Vegetable Samples ◽  
Chemical Residues ◽  
Florisil Column Chromatography ◽  
Rice Samples

Abstract A simplified method suitable for simultaneous analysis of chlorinated pesticide and phthalate ester residues in various foods was developed. Chemical residues were quantitatively extracted from fatty and vegetable samples with acetonitrile as follows: Chemical standard in 0.5 mL ethanol solution was added to 10 g homogenized sample. After 3 hr, pork and beef were extracted 3 times with 20 mL portions of acetonitrile. The acetonitrile layers were diluted with water and extracted with n-hexane. Rice samples were combined with 10 mL water, 5 mL acetonitrile, and 1 mL ethanol and extracted 3 times with 20 mL portions of n-hexane. The re-hexane concentrate from each sample was submitted to AgNO3-coated Florisil column chromatography. The AgNO3 coating adequately adsorbed interfering coextractives. Extracts of fish and vegetable samples were separated into 2 fractions by the above column chromatography. Supplemental cleanup procedures were also developed to accurately determine phthalate esters eluted in the second fraction. Satisfactory gas chromatograms were obtained for most samples.

A Method for Fractional Determination of Soybean Sterols in Four Classes by Florisil Column Chromatography

1974 ◽  
Vol 38 (9) ◽  
pp. 1661-1667
Author(s):  
Masayuki Katayama ◽  
Ching Tsang Hou ◽  
Norman C. Chen ◽  
Takako Hirota ◽  
Toshiko Kiribuchi ◽  
...  
Keyword(s):  
Column Chromatography ◽  
Florisil Column ◽  
Florisil Column Chromatography

Automated Sample Cleanup for Pesticide Multiresidue Analysis. Part II—Design and Evaluation of Column Chromatography Module

1984 ◽  
Vol 67 (4) ◽  
pp. 783-789
Author(s):  
Fred M Gretch ◽  
Joseph D Rosen
Keyword(s):  
Column Chromatography ◽  
Pesticide Residues ◽  
Continuous Flow ◽  
Flow System ◽  
Organophosphorus Pesticides ◽  
Multiresidue Analysis ◽  
Florisil Column ◽  
Continuous Flow System ◽  
Florisil Column Chromatography ◽  
Organochlorine And Organophosphorus Pesticides

Abstract An automated, continuous flow system is described for Florisil column chromatography of pesticide residues from food extracts. Evaluation of the system using 5 common organochlorine and organophosphorus pesticides in 2 crop matrices demonstrates essentially no difference in recovery or precision between automated and currently used manual analyses. The automated procedure uses only 20% of the solvents and adsorbents used in the manual procedure and is 3 times faster.

scholarly journals A method for fractional determination of soybean sterols in four classes by florisil column chromatography.

1974 ◽  
Vol 38 (9) ◽  
pp. 1661-1667 ◽  
Author(s):  
Masayuki KATAYAMA ◽  
Ching Tsang HOU ◽  
Norman C. CHEN ◽  
Takako HIROTA ◽  
Toshiko KIRIBUCHI ◽  
...  
Keyword(s):  
Column Chromatography ◽  
Florisil Column ◽  
Florisil Column Chromatography

Collaborative Study of a Method for Determination of Monosodium Glutamate in Food Products

1969 ◽  
Vol 52 (6) ◽  
pp. 1131-1132
Author(s):  
E Fernandez-Flores ◽  
Arthur R Johnson ◽  
Victor H Blomquist
Keyword(s):  
Standard Deviation ◽  
Glutamic Acid ◽  
Monosodium Glutamate ◽  
Collaborative Study ◽  
Food Products ◽  
Average Recovery

Abstract A method was collaboratively studied for the determination of monosodium glutamate as glutamic acid in food products. Six samples were submitted to each of nine collaborators. The quantity of monosodium glutamate in the samples ranged from 0.3 to 10%. The average recovery was 101.9% with a standard deviation of 3.6%. The method is recommended for adoption as official first action.

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